President Trump talking to reporters in the White House on Wednesday. (Photo: Evan Vucci/AP)

President Trump has somewhat inexplicably claimed to have invented the phrase “priming the pump.”

In an interview with the Economist published Thursday, Trump took credit for the common saying while explaining his economic philosophy. He was arguing that it’s all right for a tax plan to increase the national deficit in the short term if it spurs economic growth in the long term.

Trump asked the magazine’s editors if they understood what he meant by “we have to prime the pump.” Then he asked if they had ever heard of the phrase while claiming to have thought it up earlier this week.

“Have you heard that expression used before? Because I haven’t heard it. I mean, I just… I came up with it a couple of days ago and I thought it was good. It’s what you have to do,” Trump said.

Shortly after the interview appeared, Merriam-Webster noted that the phrase “priming the pump” dates to the early 1800s and has been used to reference government investment expenditures since at least 1933.

'Pump priming' has been used to refer to government investment expenditures since at least 1933. https://t.co/VfkGwwzZRC

Based on the transcript, it appears an Economist editor was about to correct Trump about the phrase’s origins, but the billionaire businessman hadn’t finished explaining this aspect of Trumponomics.

“Yeah, what you have to do is you have to put something in before you can get something out,” Trump said.

Merriam-Webster defines “pump priming” as “government investment expenditures designed to induce a self-sustaining expansion of economic activity.” The phrase “prime the pump,” which is filed under “prime” in the dictionary, means “to take steps to encourage the growth or functioning of something.”

Trump must know he didn’t come up with the phrase “a couple of days ago,” because he’s used it many times in the past. In March, for instance, he told the New York Times Magazine that the U.S. would need to “prime the pump” while making a similar argument.

“We’re also going to prime the pump,” Trump said then. “You know what I mean by ‘prime the pump’? In order to get this [economy] going, and going big league, and having the jobs coming in and the taxes that will be cut very substantially and the regulations that’ll be going, we’re going to have to prime the pump to some extent. In other words: Spend money to make a lot more money in the future. And that’ll happen.”